Fast and simple quantitative determination in dispersed systems (layered double hydroxides -LDHssuspensions in aqueous solutions) was performed by a procedure that couples flow injection and amperometric detection (FI-AM). LDH dispersions are injected in a continuous flow (1 mL min -1 ) of 0.05 mol L -1 KNO 3 solution and [Cu(H 2 O) 6 ] 2+ , used as a probe, is detected at a glassy carbon electrode housed in a flat electrochemical cell. The current intensity, recorded at the selected working potential (-0.25 V vs Ag/AgCl/NaCl (3 mol L -1 )), presents a linear relationship with [Cu(H 2 O) 6 ] 2+ concentration and the procedure offers high sensitivity (slope = 0.036 A/(mol L -1 )), a low detection limit (=0.7 mol L -1 ) and a wide quantification range (4-200 mol L -1 ).
The method was applied to [Cu(H 2 O) 6 ] 2+ determination in two particular LDH-aqueous solution dispersed systems: (1) [Cu(H 2 O) 6 ] 2+ scavenging by etilendiammintetraacetic acid (EDTA) modified Zn-Al-LDHs, and (2) [Cu(H 2 O) 6 ] 2+ release from a copper doped Mg-Al-LDHs. The results obtained are comparable to those reported in previous works using different quantification techniques. FI-AM determination is applied without sample pretreatment (solid-supernatant separation) providing a high sampling rate (above 120 samples h -1 ) that allows a better comprehension of the processes, particularly at the initial stages.